A ground-based augmentation system (GBAS) establishes a ground reference station with known location and differentially processes the ranging values to achieve enhanced positioning accuracy and real-time monitoring of navigation signal integrity within a region. To assess whether the navigation service provided by the installed GBAS in the local airspace (within the 50 Km centered on the GBAS ground station) meets the corresponding flight performance requirements, four aspects including accuracy, continuity, integrity and availability need to be investigated. Integrity is essential for ensuring user safety and is the most important performance requirement in the field of civil aviation navigation.
Integrity refers to the ability to issue an alarm to an on-board user in time when the navigation system cannot be used for some predetermined work during operation. The core indicators of integrity include alarm time, alarm limit, and integrity risk probability value. The integrity risk probability value refers to the probability that the system fails to be used for navigation and cannot alert the user within a specified alarm time.
However, in the prior art, the evaluation of the integrity performance has a problem of strong correlation of samples. In the case of a small number of samples, the accuracy of the integrity risk probability value is lowered, leading to low effectiveness of the evaluation.
Therefore, in order to solve some problems in the prior art, a GBAS integrity performance evaluation method based on a pseudorange error distribution model is needed.